Necessary in some cases. Workers who are happy with the general conditions of their company won't unionize. >As soon as unions become "hierarchical", Which is

Necessary in some cases. Workers who are happy with the general conditions of their company won't unionize. >As soon as unions become "hierarchical", Which is a probability that approaches 1 over time. All human endeavors tend toward hierarchies, it's just a matter of how formalized the hierarchy is and how many levels it has - but one always exists.